| 摘要 |
PURPOSE:To increase attenuation at both sides of a passing band, by adequately setting the capacity ratios of couples of electrodes of an interdigital electrode having many couples divided into two in the propagation direction and connected electrically in series. CONSTITUTION:Interdigital electrode 1 has relatively many couples, such as 30-90 couples, consists of cross-width weighting electrodes, and is divided into two partial electrodes 4 and 5 at division part 1a. Partial electrode 4 is grounded at common part 4b and has capacity C1. Partial electrode 5 is applied with input signal 1 and has capacity C2. In this case, setting C2/C1 to 1.01-1.20 increases the attenuation at both the sides of a passing band in comparison with (C2/C1)=1. |
